The following compound presentation types are provided because they implement some common idioms.
token-or-type
Summary: A compound type that is used to select one of a set of special tokens, or an object of type type . tokens is anything that can be used as the sequence parameter to member-alist ; typically it is a list of symbols.
null-or-type
Summary: A compound type that is used to select nil , whose printed representation is the special token "None," or an object of type type.
type-or-string
Summary: A compound type that is used to select an object of type type or an arbitrary string, for example:
(clim:type-or-string integer)
. Any input that
accept
cannot parse as the representation of an object of type
type
is returned as a string.
Common Lisp Interface Manager 2.0 User's Guide - 3 Mar 2015